In lighting and air conditioning systems inside buildings, it is important to conduct optimal control while accounting for factors such as energy efficiency and the comfort of the residents, using measurement values measured by measuring devices such as lighting sensors and temperature and/or humidity sensors installed in various locations inside a building. Currently, temperature and/or humidity sensors are installed on wall surfaces or the like, and are used by running communication lines inside the walls to transmit temperature and/or humidity measurement values to a controller or the like via wired communication. However, since sensors utilizing wired communication involve complicated work such as laying out communication lines, the installation costs increase. In addition, relocating the sensors is not easy.
For this reason, the wireless transmission of measurement values from a sensor equipped sensors, such as an illuminance sensor and a temperature and/or humidity sensor, (hereinafter, environmental sensor) to a controller or the like by wireless communication has been proposed. By making the environmental sensor wireless, wiring and the like become unnecessary, and installation becomes easy. There are also advantages such as flexibility in choosing the installation location of the environmental sensor, and easy relocation after installation.
Whereas, with an environmental sensor that uses wireless communication, management of the installation location becomes complicated. Particularly, if relocations occur frequently after installation of an environmental sensor, updating of the installation location becomes necessary, which is complicated. For this reason, environmental sensor position detection is conducted.
For example, in Patent Literature 1, the distance between a base station and a radio is computed from factors such as the time taken by communication between the base station and the radio, and the distances from multiple base stations are used to determine the position of the radio. Also, Patent Literature 2 discloses a system using an illuminance sensor capable of wirelessly communicating with lighting equipment, in which the emitted light level of the lighting equipment is controlled, a degree of influence of the lighting equipment with respect to illuminance measuring position is computed according to a regression coefficient calculated based on the change in the emitted light level and the change in the measured illuminance of the illuminance sensor, and control is conducted to set the measured illuminance from the illuminance sensor at a target illuminance. Furthermore, in Patent Literature 3, when a degree of influence is already known, a natural light estimation formula is computed from the total illuminance, including natural light, at an illumination sensor.